Linear and traceable scales for nanometrology

Jeremias Seppä

Research output: ThesisDoctoral ThesisCollection of Articles


Methods for the implementation of reliable, repeatable scales are central to all measurementtechniques. Laser interferometers and diffractometers can be used for accurate dimensionalmeasurements that are readily traceable to the definitions of the SI (Système International)units. This thesis is a treatise on the correction of periodic error in laser interferometry anddiffractometry and the application of interferometry and diffractometry for accuratemeasurements. Capacitive sensors and diffraction angles are used for measurement of periodicerror of laser interferometer, and laser diffractometer rotary table angle scale, resulting incorrections that can be used to attain picometre range uncertainties in laser interferometry anddiffraction grating calibration. Computational models resulting in sets of linear equations for linearization measurement data are formulated and used, resulting in Fourier-series type corrective terms for periodic errors. The developed symmetric differential heterodyne laser interferometer with the periodic errorcorrection using capacitive sensor is compared to an X-ray interferometer at National PhysicalLaboratory, UK. The results suggest that periodic nonlinearity error in the range of 10picometres and below is possible with the system. The lateral and vertical scales of IT-MAFM (the interferometrically traceable metrologicalatomic force microscope at the Centre for Metrology and Accreditation (MIKES)) areproduced with laser interferometry in the thesis. Grating standards calibrated with laserdiffractometer and characterized with IT-MAFM are used to characterize the measurementcapabilities of tens of research laboratories with scanning electron microscopes (SEMs) andAFMs in the Nordic-Baltic region. Stroboscopic scanning white light interferometry (SSWLI) is a method that can measuresurfaces and interfaces in e.g. oscillating objects in different phases of the oscillation. In thiswork, a SSWLI at the University of Helsinki is quasidynamically characterized with 2.3 nmuncertainty using a transfer standard with a vertically moving mirror, calibrated with laserinterferometry.
Translated title of the contributionLineaariset ja jäljitettävät asteikot nanometrologiassa
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
  • Ikonen, Erkki, Supervising Professor
  • Lassila, Antti, Thesis Advisor, External person
Print ISBNs978-952-60-5942-6
Electronic ISBNs978-952-60-5943-3
Publication statusPublished - 2014
MoE publication typeG5 Doctoral dissertation (article)


  • nanometrology
  • interferometry
  • nonlinearity
  • linear
  • diffractometry
  • laser
  • capacitive
  • metrology
  • AFM


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